Lantheus Holdings Inc

To the Stockholders and the Board of Directors of Lantheus Holdings, Inc.

Opinion on the Financial Statements

We have audited the accompanying consolidated balance sheets of Lantheus Holdings, Inc. and subsidiaries (the "Company") as of December 31, 2023 and 2022, the related consolidated statements of operations, comprehensive income (loss), changes in stockholders’ equity, and cash flows, for each of the three years in the period ended December 31, 2023, and the related notes (collectively referred to as the "financial statements"). In our opinion, the financial statements present fairly, in all material respects, the financial position of the Company as of December 31, 2023 and 2022, and the results of its operations and its cash flows for each of the three years in the period ended December 31, 2023, in conformity with accounting principles generally accepted in the United States of America.

We have also audited, in accordance with the standards of the Public Company Accounting Oversight Board (United States) (PCAOB), the Company's internal control over financial reporting as of December 31, 2023, based on criteria established in Internal Control - Integrated Framework (2013) issued by the Committee of Sponsoring Organizations of the Treadway Commission and our report dated February 22, 2024, expressed an unqualified opinion on the Company's internal control over financial reporting.

Basis for Opinion

These financial statements are the responsibility of the Company's management. Our responsibility is to express an opinion on the Company's financial statements based on our audits. We are a public accounting firm registered with the PCAOB and are required to be independent with respect to the Company in accordance with the U.S. federal securities laws and the applicable rules and regulations of the Securities and Exchange Commission and the PCAOB.

We conducted our audits in accordance with the standards of the PCAOB. Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the financial statements are free of material misstatement, whether due to error or fraud. Our audits included performing procedures to assess the risks of material misstatement of the financial statements, whether due to error or fraud, and performing procedures that respond to those risks. Such procedures included examining, on a test basis, evidence regarding the amounts and disclosures in the financial statements. Our audits also included evaluating the accounting principles used and significant estimates made by management, as well as evaluating the overall presentation of the financial statements. We believe that our audits provide a reasonable basis for our opinion.

Critical Audit Matter

The critical audit matter communicated below is a matter arising from the current-period audit of the financial statements that was communicated or required to be communicated to the audit committee and that (1) relates to accounts or disclosures that are material to the financial statements and (2) involved our especially challenging, subjective, or complex judgments. The communication of critical audit matters does not alter in any way our opinion on the financial statements, taken as a whole, and we are not, by communicating the critical audit matter below, providing a separate opinion on the critical audit matter or on the accounts or disclosures to which it relates.

Intangible Assets — Non-Cash Impairment Charge for AZEDRA Intangible Asset Group — Refer to Note 10 to the financial statements

Critical Audit Matter Description

In March 2023, the Company stopped all development activities in relation to a future indication associated with AZEDRA, which was classified as an in-process research and development (“IPR&D”) intangible asset. The asset group, which consisted of the IPR&D asset and a currently marketed product (the “AZEDRA intangible asset group”), was assessed for impairment. The Company considered several factors in estimating the future projections of revenues and cash flows of the AZEDRA intangible asset group as part of the impairment testing. The Company concluded that the carrying amount exceeded the fair value of the AZEDRA intangible asset group, which had no value. As a result of such assessment, the Company recorded a non-cash impairment charge in research and development expenses relating to the IPR&D asset and a non-cash impairment charge in cost of goods sold relating to the currently marketed indication of AZEDRA in the consolidated statement of operations for the year ended December 31, 2023.

We identified management’s estimates of future projections of revenue and cash flows used to determine the fair value of the AZEDRA intangible asset group used to record the non-cash impairment charge as a critical audit matter because of the significant estimates made by management. This required a high degree of auditor judgment and an increased extent of effort when performing audit procedures to evaluate the reasonableness of management’s estimates of future projections of revenues and cash flows.

How the Critical Audit Matter Was Addressed in the Audit

Our audit procedures related to management’s estimates of future revenues and cash flows used to record the non-cash impairment charge for the AZEDRA intangible asset group included the following, among others:

•We tested the effectiveness of controls over management’s review of the estimates of future projections of revenue and cash flows used to record the non-cash impairment charge for the AZEDRA intangible asset group.

•We assessed the reasonableness of management’s estimates of future projections of revenues and cash flows for the AZEDRA intangible asset group by:

◦Comparing historical results to the Company’s strategic plans.

◦Making inquiries of management and corroborating inquiries with the Company’s strategic planning group.

◦Reading internal communications to management and the Board of Directors.

•We evaluated whether the estimates of future projections of revenues and cash flows for AZEDRA were consistent with evidence obtained in other areas of the audit.

/s/ Deloitte & Touche LLP

Boston, Massachusetts

February 22, 2024

We have served as the Company’s auditor since 2007.